Motor driven time switch



1, 1965 R. J. DYK lNGA ETAL 3,282,126

MOTOR DRIVEN TIME SWITCH Filed Jan. 15, 1965 4 Sheets-Sheet 1 1956 R. J.DYKINGA ETAL 3,282,126

MOTOR DRIVEN TIME SWITCH Filed Jan. 15, 1965 4 Sheets-Sheet 2 Nov. 1,1966 J. DYKINGA ETAL 3,282,126

MOTOR DRIVEN TIME SWITCH Filed Jan. 15, 1965 1, 1965 R. J. DYKINGA ETAL3,282,126

MOTOR DRIVEN TIME SWITCH Filed Jan. 15, 1965 4 Sheets-Sheet 4 UnitedStates Patent 3,282,126 MOTOR DRIVEN TIME SWITCH Richard J. Dyiringa andRobert K. Pfleger, Miami, Fla., assignors to International RegisterCompany, Chicago, 111., a corporation of Illinois Filed Jan. 15, 1965,Ser. No. 425,752 16 Claims. (Cl. 74-568) This invention relates,generally, to motor driven devices, such as time switches, and it hasparticular relation to cam operated switches.

Among the objects of this invention are: To provide for varying in a newand improved manner the portion of a time interval that a switchoperator occupies one of two positions; to vary the portion of the timeinterval from 0% to 100% in an infinite number of steps; to provide formoving the switch operator from one position to the other position byits engagement with a cam blade that is endwise shiftable along coaxialcircular paths of different radii in a cam plate rotated at a fixedspeed, the relative extents of said paths occupied by said cam bladedetermining the portions of the time interval that the switch' operatoroccupies the two positions, the axis of. said paths being the axis ofrotation of the cam plate and the time interval being the time requiredfor one revolution thereof; to eliminate error resulting from variationin the radius of the outer surface of that portion of the cam blade inthe outer groove resulting from application of endwise stress thereto inopposite directions; and to limit the endwise movement of the cam bladewith respect to the cam plate in the 0% and 100% positions of the camblade.

According to this invention a cam plate is rotated about a fixed axis ata constant speed with the time required to make one completerevolutionbeing'the time interval during which an operator, such as aswitch operator, is to occupy one position for all or a part of theinterval or another position for all or the remaining part of theinterval. A cam lever plate is mounted for rotation with and in parallelspaced relation to the cam plate and is relatively rotatable through acomplete revolution. In the face of the cam plate toward the cam leverplate there is an outer circular groove whose axis is the axis ofrotation of these plates and it communicates by a transverse groove withan inner groove having a circular portion coaxial with the outer groove,the inner groove extending in a somewhat spiral fashion through morethan 360 and terminating in an innermost circular portion coaxial withthe outer groove. A flexible and inextensible cam blade is positionedbetween the cam plates with one edge portion extending into the groovesin the cam plate while the opposite edge is juxtaposed to and is guidedby the adjacent side of the cam lever plate. The outer end of the camblade is attached to and rotates with the cam lever plate and therebytension or compression stress is applied to the cam blade for moving italong the grooves between a position extending throughout the entireouter groove and a position extending throughout the entire inner grooveand into the innermost portion thereof. Outer and inner bosses areprovided on opposite sides of the transverse groove against whichopposite sides of the cam blade have frictional engagement therebyproviding surface loading or a clutch action to prevent the cam bladefrom moving with respect to the cam plate when the distal end of theswitch operator engages the cam blade. The outer groove is formed as aseres of chords to eliminate variations in the radial position of theouter surface of the portion of the cam blade therein due to thedirection in which stress is applied thereto for moving it endwise alongthe grooves. In one extreme position the cam blade is prevented fromfurther endwise movement by a central tongue engaging a shoulder on theinner boss.

3,282,126 Patented Nov. 1, 1966 The cam blade is prevented from furthermovement in the opposite direction when the inner end of the innermostgroove is engaged by the inner end of the cam blade. A scale, calibratedfrom 0% to 100%, is carried by a dial plate that is secured to a centershaft for rotation therewith. The cam plate also is secured to thecenter shaft. An index is carried by a set knob that is relativelyrotatably mounted on the center shaft and it indicates with respect tothe scale on the dial plate a percent of the time interval that anoperator is engaged by the outer surface of the cam blade along theportion thereof in the outer groove, the operator being spaced from theouter surface of the cam blade along the portion thereof in the innergroove for the remaining portion of the interval except for the 0% and100% settings of the index in which case for a complete revolution ofthe cam plate the operator engages the outer surface of the cam blade inthe outer groove or is spaced therefrom in the inner groove as the casemay be. The change in radial position of the operator effects acorresponding operation of a switch by shifting it, for example, fromthe open position to the closed position for the preset percent portionof the interval. Acceleration of the cam plate by snap action of thespring biased operator is prevented by frictional engagement of the backsurface of the cam plate by lugs struck from a base plate on which themotor is mounted for driving the cam plate and parts rotatabletherewith.

In the drawings:

FIG. 1 is a view, in front elevation and at full scale, of a motordriven time switch or percentage timer embodying the present invention.

FIG. 2 is a view, in rear elevation, of the construction shown in FIG.1, a portion of the back cover being broken away in order to showcertain interior details.

FIG. 3 is a view, in bottom plan, of the construction shown in FIG. 1.

FIG. 4 illustrates diagrammatically the circuits employed in practicingthis invention.

FIG. 5 -is a vertical sectional view, at an enlarged scale, takengenerally along the line 5-5 of FIG. 1, certain parts being shown inelevation.

FIG. 6 is a view, in rear elevation, of the set knob shown in FIG. 5.

FIG. 7 is a View, in end elevation and looking from right to left, ofthe center shaft shown in FIG. 5.

FIG. 8 is a view, in front elevation, of the dial plate and the scalemounted thereon.

FIG. 9 is a view, in front elevation, of the cam lever I1;lIz1(t}e,5theview being taken looking from left to right in along the line 10-10 ofFIG. 5.

FIG. 11 is a vertical sectional view taken generally along the line 1111of FIG. 5 to show only the cam plate, cam blade and the distal end ofthe switch operator.

FIG. 12 is a 'vertical sectional rview taken generally aloimg the line12-12 of FIG. 5 and at a slightly reduced sca e.

FIG. 13 is a plan view of the cam blade.

FIG. 14 is a view, in side elevation, of the cam blade shown in FIG. 13.

In FIGS. 1, 2 and 3 the reference character 10 desighates, generally, amotor driven time switch or percentage timer which includes a metalliccase, indicated generally at 11. The metallic case 1 1 is formed by afront wall 12 that is united integrally with a top wall 13, side walls14 and 15, and a bottom wall 16. A slot 17 is formed in the bottom wall16 for receiving a conduit or the like to facilitate connection of thenecessary electrical conductors to the time switch 10. Up struck tabs 18are formed on the bottom wall 16 for insertion through openings 19 in abottom flange 20 that is integral with a metallic back cover 21, FIG. 5,thereby providing a detachable hinge construction. A circular opening 22is formed in the bottom flange 20 to register with the slot 17. Sideflanges 23 extend forwardly from the back cover 2 1 for fitting insideof the side walls 14 and 15. A top flange 24 extends underneath the topwall 13 of the metallic case 11 and a screw 25 extends through thelatter into the former to secure the back cover 21 in place.

In FIG.. base plate studs 27 extend rearwardly from the 'front wall 12for supporting a metallic base plate 28. Screws 27' extend through themetallic base plate, FIG. 2, for securing it in position within themetallic case 11.

The base plate 28 has an offset lower portion 29 from which switch studs'30 ext-end forwardly and are held in position by screws 31. Forwardlyof spacer sections 32 on the switch studs 30 the-re is mounted aninsulating housing 33 of a switch that is indicated, generally, at 34and is shown more clearly in FIG. 12. The switch 34 is a spring biasedover center switch and can be a single pole, single throw switch, asingle pole, double throw switch, a double pole, single throw switch ordouble throw, etc. An operator 35 is arranged to shift the movableelement of the switch 34 from one significant position to another inwhich the over center biasing action of the switch opens or closes itscontacts as the case may be and wit-h a snap action. Its distal end 36is arranged to be moved in a manner to be described against a biasingspring incorporated in the switch 34, the biasing spring acting to movethe operator 35 and the switch to Mounted on the rear side of the baseplate '28 by screws 39, FIG. 2, is .a synchronous timing motor that isindicated, generally, at 40. The timing motor 40 is indicateddiagrammatically in FIG. 4 where it is shown as being connected forenergization across conductors 41 'and 42 that may be energized from asuitable alternating current source such as llS-volt 60-cycle source.The switch 34 is illustrated as being interposed on the conductor 41between the line and the load. The motor driven time switch is arrangedto maintain the contacts of the switch 34 in closed position for apreset percent portion of a time interval, for example for one-halfminute or 20% of a two and a one-half minute interval.

FIG. 5 shows the motor 40 arranged to drive a pinion 43 that ispositioned on the front side of the base plate 28. The pinion 43 isdriven through a suitable gear reduction by the motor 40 so that itrotates at a relatively slow speed. For example, it may rotate at aspeed of 2 revolutions per minute. The pinion 43 drives a gear 44 andthe gear ratio is such that the gear 44 is rotated at a speed of 1revolution each two and one-half minutes. Obviously, other gear ratioscan be employed as may be desired.

Extending forwardly from and formed integrally with the gear 44 are lugs45. They project into slots 46 that are located in a ring portion 47formed integrally with the rear side of a cam plate 48 that may beformed of nylon or like plastic material. FIG. 11 shows the cam plate 48as being provided with a central opening 49 having fiat sides 50 and 51for no-nrotatable mounting on flat sides 52 and 53, respectively, of acenter shaft 54 an end view of which is shown in 'FIG. 7. One end 55 ofthe center shaft 54 is journaled in a bearing opening 56, FIG. 5, in thebase plate 28. A coil compression spring 57 is interposed between thefront side of the gear 44 and a bottom surface 58 of a cavity 58 whichis formed in the rear side of the cam plate 48. The spring 57 functionsto hold the cam plate 48 in its proper position along the center shaft54 in conjunction with certain other associated parts to be described.The assembly is held in place on the center shaft 54 by a C-snap washer60 which fits into an annular groove 61 at the inner end of the centershaft 54. Both the gear 44 and the cam plate 48 rotate together with thecenter shaft 54 as driven by the pinion 43 from the motor 40.

Adjacent its forward end the center shaft 54 is journaled in a circularbearing opening 64, FIG. 6, that is formed in a hub 65 which is integralwith a set knob 66, preferably formed of nylon or like material, andmounted in front of the front wall 12 of the metallic case 11 as shownin FIGS. 1 and 5 with a slight clearance 66' therebetween. The hub '65of the set knob 66 has a circular bearing surface 67 that is journaledin a hearing opening 68 in the front wall 12. It will be understood thatthe set knob 66 is arranged to rotate on manual setting relative to thecenter shaft 54 and that, once set, is arranged to rotate conjointlytherewith. The set knob 66, FIG. 1, carries an index 69 that is movablewith respect to a scale 70, FIG. 8, which is carried by a dial plate 71.Thescale 70 is provided with markings ranging from 0% to 100% forregistration with the index 69 with respect to which the scale 78 anddial plate 71 are arranged to rotate through 360 in one direction or theother. This provides for full range of adjustment from 0% to 100% of thetime interval.

FIG. 5 shows the dial plate 71 mounted for rotation with the centershaft 54, the cam plate 48 and the gear 44. For this purpose the dialplate 71, FIG. 8, has a central opening 73 with fiat sides 74 and 75that are arranged to overlie the flat sides 52 and 53 of the centershaft 54. Since the set knob 66 is rotatable relative to the dial plate71 for adjustment purposes, it is desirable to have controlledfrictional engagement therebetween without deformation of the dial plate71. Accordingly, the set knob 66 has an annular rib 76, FIG. 5, that isformed integrally therewith and is arranged to have contact engagementalong a circle with the rear surface of the dial plate 71 withsufficient friction to prevent slippage due to frictional loadingapplied to the cam plate 48 by the spring 57.

Mounted for rotation with the set knob 66 is a metallic cam lever plate78. FIG. 9 shows the cam leverplate 78 as provided with a centralopening 79 having flat sides 80 and 81 to overlie flat sides 82 and 83,FIG. 6, on the hub 65 of the set knob66. The cam lever plate 78 has anoffset central flange 84 surrounding the central opening 79 for engagingon its front surface rearwardly facing surfaces 82' and 83' on the hub65 that extend outwardly at right angles from the flat sides 82 and 83,respectively.

As pointed out the construction and arrangement of the center shaft 54are such that the gear 44, cam plate 48 and dial plate 71 are rotatabletherewith while the set knob 66 and the cam lever plate 78 are'rotatablymounted on the center shaft 54 for adjustment of the index 69 along thescale 70. A circular head 72 at the outer end of the center shaft 54functions to hold the set knob 66 and dial plate 71 in proper position.The axis of rotation of the center shaft 54 is indicated by broken line85. It will be apparent that this is also the axis of rotation of thecam plate 48 and the lever plate 78 that is mounted in parallel spacedrelation forwardly thereof. Also it is the axis of rotation of the setknob 66 and of the dial plate 71.

The time during each rotationof the cam plate 48 that the operator 35occupies the position shown in FIG. 12 is controlled by ,a cam blade 86,FIGS. 11, 13 and 14. The cam blade 86 is preferably formed of a flexibleinextensible relatively thin material such as an elongated sheet ofstainless steel. At one end cam blade 86 has a finger 87 which isprovided with openings 88 for receiving ends 89 of hooks 90, FIGS. 5, 9and 10, which are formed with a radially extending offset section 91 ofthe cam lever plate 78. Through the connection thus provided between thecam lever plate 78 and the cam blade 86 it is possible to apply atension or a compression stress thereto for moving it in one directionor the other depending upon the direction in which the cam lever plate78 is rotated on rotation of the set knob 66. Opposite the finger 87 andat the same end there is provided the guide finger 92 the function ofwhich will be set forth presently. Near the other end of the cam blade86 a slot 93 is provided in the same side from which the finger 87extends for the purpose of clearing it and its connection to the camlever plate 78 when the time switch is set for the 100% position. Inorder to arrest further movement of the set knob 66 in the 100% positionthere is formed a stop tongue 94 intermediate the sides of the cam blade86. The stop tongue 94 is formed by cutting away a U-shaped opening 95.The other end 96 of the cam blade 86 is turned upwardly to preventcutting into the walls of the inner groove 104 when the cam blade 86 ispushed inwardly therealong. The turned up end 96 functions as a stop tolimit further movement of the cam blade 86 in the 0% setting.

FIG. 11 shows the cam plate 48 as being provided with an outer circulargroove 99 the center of which is the axis 85 of rotation of the centershaft 54 and of the cam plate 48. An edge portion 100 of the flexiblecam blade 86 is located within the outer circular groove 99 as shown inFIG. 11. It will be noted that the outer circular groove 99 is formed bya series of relatively short chords 101. The reason for this is to makecertain that the outer surface 102 of the cam blade 86 against which thedistal end 36 of the operator 35 bears is always at a fixed radius fromthe axis 85 and that this radius does not vary, de-' pending uponwhether a tension or a compression stress is applied to the cam blade 86by the set knob 66. The

outer circular groove 99 is opposite the books 90 to which the finger 87is attached.

The cam blade 86 is somewhat longer than the cir- 'cumference of theouter circular groove 99. Its edge portion 100 extends through atransverse groove 103 to an inner groove 104 which has a circularportion the center of which is the axis 85. The radial distance 105between the outer surface 102 of the cam blade 86 in the outer circulargroove 99 and the outer surface 102 in the inner groove 104 issubstantially greater than the minimum distance required to effectpositive movement of the operator 35 from one significant position tothe other significant position.-

The inner groove 104 extends in a somewhat'spiral fashion along aninnermost circular portion 106 which is of sufficient length togetherwith the initial portion of the inner groove 104 to accommodate theentire length of the cam blade 86. In this position the outer surface102 of the cam blade 86 is located at the minimum radial distance fromthe axis 85 and is spaced from the distal end 36 of the operator 35.Thus for a complete revolution of the cam plate 48 with the 'cam blade86 in the position just described the distal end 36 of the operator 35is free of'engagement with the cam blade 86 and it occupies a positionwhich may be considered to be the 0% position during which the operator35 is in the corresponding significant position. When the other end 96of the cam blade 86 engages the end 107 of the innermost circularportion 106, further inward movement of the cam blade 86 is arrested.This forms one of the stops for endwise movement of the camblade 86.

FIG. 11 shows outer and inner bosses 110 and 111 integral with the camplate 48 and flanking the transverse groove 103 on opposite sides fordirecting the edge portion 100 of the cam blade 86 in its movement fromthe outer circular groove 99 to the inner groove 104. A stop shoulder112 on the inner boss 111 is arranged to be engaged by .the stop tongue94 on the cam blade 86 to limit further rotation of the set knob 66 in aposition that corresponds to the position of the index 69 with respectto the scale 70 in which the cam blade 86 eX-, tends substantiallythroughout the entire extent of the outer circular groove 99 so that,for this setting, the operator 35 is held in the significant positionshown in FIG. l2 for a complete revolution of the cam plate 48.

A slot 113, FIG. 13, between the finger 87 and guide finger '92accommodates movement of the distal end 36 of the operator 35. The guidefinger -92 acts as an extension of the edge portion 100 of the cam blade86 to direct it in its movement along the outer circular groove 99.

When the distal end 36 of the operator 35 moves radially inwardly fromengagement with the outer surface 102 of the cam blade 86 in the outercircular groove 99, there is a tendency for it to accelerate themovement of the cam plate 48. In order to prevent this, lugs 114, FIGS.10 and 12, are struck from the base plate 28 and extend forwardly. Theyare provided with bumps 115 which have small area contact engagementwith the rear side 116 of the cam plate 48. This provides sufiicientfrictional engagement to dampen such acceleration.

It will be noted in FIG. 11 that the outer surface 117 of the outer boss110 is at a slightly less radial distance from the axis 85 than is theouter surface 102 of the cam blade 86 in the outer circular groove 99.Thus, when the distal end 36 of the operator 35 is disengaged from theouter surface 102 as the cam plate 48 is rotated in the directionindicated by arrow 118, it is transferred to the outer surface 117 ofthe outer boss 110. Where the cam blade 86 extends from the outercircular groove 99 to the transverse groove 103, a small radius bend 119is formed. As the distal end 36 is engaged by the bend 119, it is movedinwardly by the action of the over center spring of the switch 34. Thismovement is sufiicient' to effect over center operation of the switch 34which, be cause of its individual spring action, is independent of thespeed at which the bend 119 is rotated by the mo tor 40.

On the continued rotation of the cam plate 48 in the direction of thearrow 118, the distal end 36 of the operator 35 engages edge 120 of theslot 113 between the fingers 87 and 92 and thus is moved to a positionwhere the outer surface 102 of the cam blade 86 in the outer circulargroove 99 is engaged, thereby effecting a corre sponding shift in theposition of the switch 34.

As noted, the cam blade 86 extends along a small radius bend 119, FIG.11, in its transition from the outer circular groove 99 to thetransverse groove 103. Likewise it extends along a small radius bend 121in its transi tion from the transverse groove 121 to the inner groove104. Thus inner surface 122 of the cam blade 86 is di rected intofrictional engagement with a flat surface 123 on the inner boss 111 andthe outer surface 102 is directed into frictional engagement with flatsurfaces 124 and 125 on the outer boss.110. These frictional engagementsef fect surface loading or a slippable clutch action between the camplate 48 and the cam blade 86 which prevents relative movementtherebetween while permitting such movement on manual rotation of theset knob '66 which applies a tension or compression force to the camblade 86 to pull or push it along the outer and inner circular grooves99 and 104 depending on the direction of rotation of the set knob 66.

What is claimed as new is:

1. A device for controlling the portion of a time inter val that ashiftable operator occupies one of two positions comprising: a cam plateadapted to be rotated about an axis at a predetermined speed, said camplate having in one face a circular outer groove coaxial with said axisand an inner groove connected by a transverse groove to said outergroove with that portion of said inner groove extending from saidtransverse groove being circular and coaxial with said axis, a cam leverplate adapted to be manually rotated about said axis and having one sidein parallel spaced relation to said face of said cam plate, and aflexible cam blade secured at one end to said cam lever plate, with oneedge being juxtaposed to and guided on said one side of said cam leverplate; the other edge of said cam blade extending into and being guidedby said outer groove, transverse groove and inner groove and slidabletherealong in accordance with relative rotation of said cam lever platewith respect to said cam plate;

the outermost surface of said cam blade being engageable with said'shiftable operator for effecting movement thereof from one of saidpositions to the other in accordance with the position of said cam bladealong said grooves.

2. A device for controlling the portion of a time interval that ashiftable operator occupies one of two positions comprising: a cam plateadapted to be rotated about an axis at a predetermined speed, said camplate having in one face a circular outer groove coaxial with said axisand an inner groove connected by a transverse groove to said outergroove with that portion of said inner groove extending from saidtransverse groove being circular and coaxial with said axis, said innergroove having another portion extending from said circular portionthereof and within said circular portion, a cam lever plate adapted tobe manually rotated about said axis and having one side in parallelspaced relation to said face of said earn plate, and a flexible camblade secured at one end to said cam lever plate with one edge beingjuxtaposed to and guided on said one side of said cam lever plate; theother edge of said cam blade extending into and being guided by saidouter groove, transverse groove and inner groove and slidable therealongin accordance with relative rotation of said cam lever plate withrespect to said cam plate; the outermost surface of said cam blade beingengageable with said shiftable operator for effecting movement thereoffrom one of said positions to the other in accordance with the positionof said cam blade along said grooves.

3. A device for controlling the portion of a time interval that ashiftable operator occupies one of two positions comprising: a cam plateadapted to be rotated about an axi at a predetermined speed, said camplate having in one face a circular outer groove coaxial with said axisand an inner groove connected by a transverse groove to said outergroove with that portion of said inner groove extending from saidtransverse groove being circular and coaxial with said axis, said innergroove having another portion extending from said circular portionthereof and within said circular portion, a cam lever plate adapted tobe manually rotated about said axis and having one side in parallelspaced relation to said face of said cam plate, a flexible cam bladesecured at one end to said cam lever plate with one edge beingjuxtaposed to and guided on said one side of said cam lever plate; theother edge of said cam blade extending into and being guided by saidouter groove, transverse groove and inner groove and slidable therealongin accordance with relative rotation of said cam lever plate withrespect to said cam plate; the outermost surface of said cam blade beingengagea'ble with said shiftable operator for effecting movement thereoffrom one of said positions to the other in accordance with the positionof said cam blade along said grooves, the other end of said cam bladebeing engageable with an end of said other portion of said inner grooveto limit relative rotation of said cam plate and cam lever plate in onedirection, and stop means on said cam blade engageable with abutmentmeans on said cam plate to limit relative rotation thereof with respectto said cam lever plate in the opposite direction.

'4. The device as claimed in claim 1 wherein said circular outer grooveis formed in part at least as a series of chords to maintain the outersurface of that portion of said cam blade in said outer groove at a.substantially uniform distance from said axis regardless of thedirection in which force is applied endwise to said cam blade in movingit along said grooves.

5. The device as claimed in claim 1 wherein said transverse groove isflanked by inner and outer bosses to direct sliding movement of saidflexible earn blade along said transverse groove and between said outerand inner grooves and to effect a slippable clutch action betweensurfaces of said bosses and the juxtaposed surfaces of said cain blade.

6. The device as claimed in claim 5 wherein the transition portions ofsaid carn blade at the ends of said transverse groove are small radiusbends and opposite sides of said cam blade have surface contactengagement with fiate surfaces on said bosses.

7. The device as claimed in claim 5 wherein said earn blade carries stopmeans engageable with ashoulder on said inner boss to limit relativerotation inone direction of said cam plate and said cam lever plate.

8. A device for conrtolling the portion of a time interval that ashiftable operator occupies one of two positions comprising: a shaftadapted to be rotated at a predetermined speed, a cam plate rnounted onsaid shaft for rotation therewith, said cam plate having in one face acircular outer groove coaxial with the axis of rotation of said shaftand cam plate and an inner groove connected by a transverse groovetosaid outer groove with that portion of aid inner groove extending fromsaid transverse groove being circular and coaxial with said axis, a dialplate mounted on said shaft for rotation therewith and carrying acircular scale, a set knob rotatably mounted on said shaft adjacent saiddial plate, an index on said set knob for variably registering with saidscale, a cam lever plate mounted on said set knob for rotation therewithand having one side in parallel spaced relation to said face of saidca-m plate, and a flexible cam blade secured at one end to said camlever plate with one edge being juxtaposed to and guided on said oneside of said cam lever plate; the other edge of said cam blade extendinginto and being guided by said outer groove, transverse groove and innergroove and slidable therealong in accordance with relative rotation ofsaid index with respect to said scale; the outermost surface of said camblade being engageable with said shiftable operator 'for effectingmovement thereof from oneof said positions, to the other in accordancewith the position of said cam blade along said grooves.

9. The device as claimed in claim 8 wherein said inner groove hasanother portion extending from and within said circular portion thereof.

10. The device as claimed in claim 9 wherein the other end of said earnblade is engageable with an end of said other portion of said innergroove to limit relative rotation of said cam plate and cam lever platein one direction, and stop means on said cam blade engageable withabutment means on said cam plate to limit-relative rotation thereof withrespect to said cam lever plate in the opposite direction.

11. The device as claimed in claim 8 wherein said circular groove isformed throughout substantially its entire extent as a series of chordsto maintain the outer surface of that portion of said cam blade in saidouter groove at a substantially uniform distance from said axisregardless of the drection in which force is applied endwise to said camblade in moving it along said grooves.

12. The device as claimed in claim 8 wherein said transverse groove isflanked by inner and outer bosses secured to said cam plate andextending toward and in spaced relation to said one side of saidcamlever plate to direct sliding movement of said one edge of said flexiblecam blade along said transverse groove and between said outer and innergrooves and to provide a slipp-able clutch action the-rebetween. I

13. The device as claimed in claim 12 wherein the transition portions ofsaidblade at the ends of said transverse groove are small radius bendsand opposite sides of said cam blade have surface contact engagementwith flat surfaces on said bosses.

14. The device as claimed in claim 12 wherein said cam blade has a stoptongue engageable with a shoulder on said inner boss to limit relativerotation in one direction of said cam plate and said cam lever plate.

15. A device for controlling the portion of a time interval that ashiftable operator occupies one of two positions comprising: a cam plateadapted to be rotated about an axis at a predetermined speed, said camplate having in one face a circular outer groove coaxial with said axisand an inner groove connected by a transverse groove being circular andcoaxial with said axis, a cam lever plate adapted to be manually rotatedabout said axis and having one side in parallel spaced relation to saidface of said cam plate, and 'a flexible cam blade secured at one end tosaid cam lever plate at a location opposite said outer groove, one edgeof said cam blade being juxtaposed to and guided on said one side ofsaid cam lever plate; the other edge of said cam blade extending intoand being guided by said outer groove, transverse igroove and innergroove and slidable therealong in accordance with relative rotation ofsaid cam lever plate with respect to said cam plate; the outermostsurface of said cam blade being engageable with said shiftable operatorfor effecting movement thereof from one of said positions to the otherin accordance with the position of said cam blade along said grooves.

16. A device for controlling the portion of a time interval that ashiftable operator occupies one of two positions comprising: a shaftadapted to be rotated at a predetermined speed, a cam plate mounted onsaid shaft for rotation therewith, said cam plate having in one face acircular outer groove coaxial with the axis of rotation of said shaftand cam plate and an inner groove connected by a transverse groove tosaid outer groove with that portion of said inner groove extending fromsaid trans verse groove being circular and coaxial with said axis, adial plate mounted on said shaft for rotation therewith and carrying acircular scale, a set knob rotatably mounted on said shaft adjacent saiddial plate, an index on said set knob for variably registering with saidscale, a cam lever plate mounted on said set knob for rotation therewith and having one side in parallel spaced relation to said face ofsaid cam plate, and a flexible cam blade secured at one end to said camlever plate at location op posite said outer groove, one edge of saidca-m blade being juxtaposed to and guided on said one side of said camlever plate; the other edge of said cam blade extending into and beingguided .by said outer groove, transverse groove and inner groove andslidable therealong in accordance with relative rotation of said indexwith respect to said scale; the outermost surface of said cam bladebeing engageable with said shiftable operator for effecting movementthereof from one of said positions to the other in accordance with theposition of said cam blade along said grooves.

References Cited by the Examiner UNITED STATES PATENTS 1/1941 HaesZOO-36 1/1945 Pattee.

1. A DEVICE FOR CONTROLLING THE PORTION OF A TIME INTERVAL THAT ASHIFTABLE OPERATOR OCCUPIES ONE OF TWO POSITIONS COMPRISING: A CAM PLATEADAPTED TO BE ROTATED ABOUT AN AXIS AT A PREDETERMINED SPEED, SAID CAMPLATE HAVING IN ONE FACE A CIRCULAR OUTER GROOVE COAXIAL WITH SAID AXISAND AN INNER GROOVE CONNECTED BY A TRANSVERSE GROOVE TO SAID OUTERGROOVE WITH THAT PORTION OF SAID INNER GROOVE EXTENDING FROM SAIDTRANSVERSE GROOVE BEING CIRCULAR AND COAXIAL WITH SAID AXIS, A CAM LEVERPLATE ADAPTED TO BE MANUALLY ROTATED ABOUT SAID AXIS AND HAVING ONE SIDEIN PARALLEL SPACED RELATION TO SAID FACE OF SAID CAM PLATE, AND AFLEXIBLE CAM BLADE SECURED AT ONE END TO SAID CAM LEVER PLATE, WITH ONEDEGE BEING JUXTAPOSED TO AND GUIDED ON SAID ONE SIDE OF SAID CAM LEVERPLATE; THE OTHER EDGE OF SAID CAM BLADE EXTENDING INTO AND BEING GUIDEDBY SAID OUTER GROOVE, TRANSVERSE GROOVE AND INNER GROOVE AND SLIDABLETHEREALONG IN ACCORDANCE WITH RELATIVE ROTATION OF SAID CAM LEVER PLATEWITH RESPECT TO SAID CAM PLATE; THE OUTERMOST SURFACE OF SAID CAM BLADEBEING ENGAGEABLE WITH SAID SHIFTABLE OPERATOR FOR EFFECTING MOVEMENTTHEREOF FROM ONE OF SAID POSITIONS TO THE OTHER IN ACCORDANCE WITH THEPOSTION OF SAID CAM BLADE ALONG SAID GROOVES.